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<details class="folding-tag" blue><summary> 点击查看使用工具及版本 </summary>
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              <table>    <tr>        <td align="center" width=150px>Windows</td>        <td align="left">windows11</td>    </tr>    <tr>        <td align="center">Ubuntu</td>        <td align="left">Ubuntu16.04的64位版本</td>      </tr>    <tr>        <td align="center">VMware® Workstation 16 Pro</td>        <td align="left">16.2.3 build-19376536</td>      </tr>    <tr>        <td align="center">SecureCRT</td>        <td align="left">Version 8.7.2 (x64 build 2214)   -   正式版-2020年5月14日</td>      </tr>    <tr>        <td align="center">开发板</td>        <td align="left">正点原子 i.MX6ULL Linux阿尔法开发板</td>      </tr>    <tr>        <td align="center">uboot</td>        <td align="left">NXP官方提供的uboot，NXP提供的版本为uboot-imx-rel_imx_4.1.15_2.1.0_ga(使用的uboot版本为U-Boot 2016.03)</td>      </tr>    <tr>        <td align="center">linux内核</td>        <td align="left">linux-4.15(NXP官方提供)</td>      </tr>    <tr>        <td align="center">STM32开发板</td>        <td align="left">正点原子战舰V3(STM32F103ZET6)</td>      </tr></table>
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<h1 id="一、System-V-消息队列"><a href="#一、System-V-消息队列" class="headerlink" title="一、System V 消息队列"></a><font size=3>一、System V 消息队列</font></h1><p>前边我们知道<code>System V IPC</code>经过优化出现了<code>POSIX IPC</code>，消息队列的话也就会有两种，这里所学习的是<code>System V IPC</code>的消息队列。</p>
<h2 id="1-相关概念"><a href="#1-相关概念" class="headerlink" title="1. 相关概念"></a><font size=3>1. 相关概念</font></h2><p>消息队列是<code>System V IPC</code>中的一种，它的底层是一个链队列，与共享内存的不同是，内核要保证消息队列的<code>FIFO</code>性质，因此当有多个接收方进程接收消息队列中的消息的时候，不会产生冲突，由内核来协调他们的执行顺序。由于队列性质，队尾写，队头读，所以读写也不会存在冲突。</p>
<p>进程间通过<code>IPC</code>消息队列通信时，进程产生的每条消息都被发送到一个<code>IPC</code>消息队列中，这个消息一直存放在队列中，直到另外一个进程将其读走，故消息只适用于两个进程间通信。消息是由固定大小的首部，该首部是一个<code>long int</code> 型，用来存放消息类型和可变长度的正文组成。</p>
<h2 id="2-消息队列特点"><a href="#2-消息队列特点" class="headerlink" title="2. 消息队列特点"></a><font size=3>2. 消息队列特点</font></h2><p>消息队列有如下特点：</p>
<ul>
<li><p>消息队列由消息队列<code>ID</code>来唯一标识。</p>
</li>
<li><p>消息队列就是一个消息的列表，用户可以在消息队列中添加消息、读取消息等。</p>
</li>
<li><p>消息队列可以按照类型来发送或者接收消息。</p>
</li>
</ul>
<h2 id="3-消息队列在内核的形式"><a href="#3-消息队列在内核的形式" class="headerlink" title="3. 消息队列在内核的形式"></a><font size=3>3. 消息队列在内核的形式</font></h2><img data-src="https://fanhua-picture.oss-cn-hangzhou.aliyuncs.com/01%E5%B5%8C%E5%85%A5%E5%BC%8F%E5%BC%80%E5%8F%91/01HQ%E8%AF%BE%E7%A8%8B%E4%BD%93%E7%B3%BB/LV05-%E6%93%8D%E4%BD%9C%E7%B3%BB%E7%BB%9F/LV05-05-%E8%BF%9B%E7%A8%8B%E9%80%9A%E4%BF%A1-05-%E6%B6%88%E6%81%AF%E9%98%9F%E5%88%97/img/image-20220609181315642.png" alt="image-20220609181315642" style="zoom:50%;" />

<h2 id="4-如何使用消息队列？"><a href="#4-如何使用消息队列？" class="headerlink" title="4. 如何使用消息队列？"></a><font size=3>4. 如何使用消息队列？</font></h2><h3 id="4-1-发送消息端"><a href="#4-1-发送消息端" class="headerlink" title="4.1 发送消息端"></a><font size=3>4.1 发送消息端</font></h3><p>消息队列发送端的使用步骤一般如下：</p>
<p>（1）申请<code>key</code>，用于不同的进程的话，可以使用<code>ftok()</code>函数实现，若是用于具有血缘关系的进程，则也可以是<code>IPC_PRIVATE</code>。</p>
<p>（2）打开或者创建消息队列，通过<code>msgget()</code>函数实现。</p>
<p>（3）向消息队列发送消息，通过<code>msgsnd</code>实现。</p>
<h3 id="4-2-接收消息端"><a href="#4-2-接收消息端" class="headerlink" title="4.2 接收消息端"></a><font size=3>4.2 接收消息端</font></h3><p>消息队列接收端的是哦用步骤一般如下：</p>
<p>（1）申请<code>key</code>，用于不同的进程的话，可以使用<code>ftok()</code>函数实现，若是用于具有血缘关系的进程，则也可以是<code>IPC_PRIVATE</code>。保证与发送端相同，以使用同一个<code>IPC</code>对象<code>ID</code>。</p>
<p>（2）打开或者创建消息队列，通过<code>msgget()</code>函数实现。</p>
<p>（3）从消息队列接收消息，通过 <code>msgrcv()</code>函数实现。</p>
<p>（4）控制（删除）消息队列，通过<code>msgctl()</code>函数实现。</p>
<h1 id="二、消息队列基本操作"><a href="#二、消息队列基本操作" class="headerlink" title="二、消息队列基本操作"></a><font size=3>二、消息队列基本操作</font></h1><h2 id="1-打开或创建消息队列"><a href="#1-打开或创建消息队列" class="headerlink" title="1. 打开或创建消息队列"></a><font size=3>1. 打开或创建消息队列</font></h2><h3 id="1-1-msgget"><a href="#1-1-msgget" class="headerlink" title="1.1 msgget() "></a><font size=3>1.1 msgget() </font></h3><p>在<code>linux</code>下可以使用<code>man 2 msgget</code>命令查看该函数的帮助手册。</p>
<figure class="highlight c"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment">/* 需包含的头文件 */</span></span><br><span class="line"><span class="meta">#<span class="keyword">include</span> <span class="string">&lt;sys/types.h&gt;</span></span></span><br><span class="line"><span class="meta">#<span class="keyword">include</span> <span class="string">&lt;sys/ipc.h&gt;</span></span></span><br><span class="line"><span class="meta">#<span class="keyword">include</span> <span class="string">&lt;sys/msg.h&gt;</span></span></span><br><span class="line"></span><br><span class="line"><span class="comment">/* 函数声明 */</span></span><br><span class="line"><span class="type">int</span> <span class="title function_">msgget</span><span class="params">(<span class="type">key_t</span> key, <span class="type">int</span> msgflg)</span>;</span><br></pre></td></tr></table></figure>

<p><strong>【函数说明】</strong>该函数打开或者创建一个消息队列，获取消息队列的<code>IPC</code>对象<code>ID</code>。</p>
<p><strong>【函数参数】</strong></p>
<ul>
<li><code>key</code>：<code>key_t</code>类型，通过<code>ftok</code>创建的<code>key</code>（键）值或者是<code>IPC_PRIVATE</code>（这样的话只能用于具有血缘关系的进程通信）。</li>
<li><code>shmflg</code>：<code>int</code>类型，共享内存标志位，使用时需要与<code>IPC</code>对象存取权限（如<code>0666</code>）进行<code>|</code>运算来确定读写权限。一般是需要创建共享内存时为<code> IPC_CREAT|0666</code>，若不需要创建，直接打开时，使用<code>0666</code>即可。</li>
</ul>
<details class="folding-tag" blue><summary> 点击查看常用可取的值及含义 </summary>
              <div class='content'>
              <table>    <tr><td align="center" width=150px>IPC_CREAT</td><td align="left">如果共享内存不存在，则创建一个共享内存，否则打开操作。</td></tr>    <tr><td align="center" width=150px>IPC_EXCL </td><td align="left">只有在共享内存不存在的时候，新的共享内存才建立，否则就产生错误。</td></tr></table><ul><li><p>如果单独使用<code>IPC_CREAT</code>，<code>msgget()</code>函数要么返回一个已经存在的消息队列的标识符，要么返回一个新建的消息队列的标识符。</p></li><li><p>如果将<code>IPC_CREAT</code>和<code>IPC_EXCL</code>标志一起使用，<code>msgget()</code>将返回一个新建的消息队列的标识符；如果该消息队列已存在，就会返回错误。</p></li></ul>
              </div>
            </details>

<p><strong>【返回值】</strong><code>int</code>类型，成功返回消息队列的标识符，也就是消息队列<code>ID</code>，失败返回<code>-1</code>，并设置<code>errno</code>。</p>
<p><strong>【使用格式】</strong>一般情况下基本使用格式如下：</p>
<figure class="highlight c"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment">/* 需要包含的头文件 */</span></span><br><span class="line"><span class="meta">#<span class="keyword">include</span> <span class="string">&lt;sys/types.h&gt;</span></span></span><br><span class="line"><span class="meta">#<span class="keyword">include</span> <span class="string">&lt;sys/ipc.h&gt;</span></span></span><br><span class="line"><span class="meta">#<span class="keyword">include</span> <span class="string">&lt;sys/msg.h&gt;</span></span></span><br><span class="line"><span class="comment">/* 至少应该有的语句 */</span></span><br><span class="line"><span class="type">key_t</span> key;</span><br><span class="line"><span class="type">int</span> msgid;</span><br><span class="line">key = ftok(<span class="string">&quot;./key.txt&quot;</span>, <span class="number">100</span>);</span><br><span class="line">msgid = msgget(key, IPC_CREAT|<span class="number">0666</span>);</span><br></pre></td></tr></table></figure>

<p><strong>【注意事项】</strong><code>none</code></p>
<h3 id="1-2-使用实例"><a href="#1-2-使用实例" class="headerlink" title="1.2 使用实例"></a><font size=3>1.2 使用实例</font></h3><p>暂无。</p>
<h2 id="2-发送消息"><a href="#2-发送消息" class="headerlink" title="2. 发送消息"></a><font size=3>2. 发送消息</font></h2><h3 id="2-1-msgsnd"><a href="#2-1-msgsnd" class="headerlink" title="2.1 msgsnd() "></a><font size=3>2.1 msgsnd() </font></h3><p>在<code>linux</code>下可以使用<code>man 2 msgsnd</code>命令查看该函数的帮助手册。</p>
<figure class="highlight c"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment">/* 需包含的头文件 */</span></span><br><span class="line"><span class="meta">#<span class="keyword">include</span> <span class="string">&lt;sys/types.h&gt;</span></span></span><br><span class="line"><span class="meta">#<span class="keyword">include</span> <span class="string">&lt;sys/ipc.h&gt;</span></span></span><br><span class="line"><span class="meta">#<span class="keyword">include</span> <span class="string">&lt;sys/msg.h&gt;</span></span></span><br><span class="line"></span><br><span class="line"><span class="comment">/* 函数声明 */</span></span><br><span class="line"><span class="type">int</span> <span class="title function_">msgsnd</span><span class="params">(<span class="type">int</span> msqid, <span class="type">const</span> <span class="type">void</span> *msgp, <span class="type">size_t</span> msgsz, <span class="type">int</span> msgflg)</span>;</span><br><span class="line"></span><br></pre></td></tr></table></figure>

<p><strong>【函数说明】</strong>该函数向消息队列发送一个消息。</p>
<p><strong>【函数参数】</strong></p>
<ul>
<li><code>msqid</code>：<code>int</code>类型，消息队列<code>ID</code>。</li>
<li><code>msgp</code>：<code>void *</code>类型，要发送的消息的缓冲区地址，一般是指向一个我们<strong>自定义</strong>的<strong>特定格式</strong>的结构体变量，这个结构体变量中存储的是消息的类型和消息的正文。</li>
</ul>
<details class="folding-tag" blue><summary> 点击查看指向的结构体一般格式 </summary>
              <div class='content'>
              <figure class="highlight c"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br></pre></td><td class="code"><pre><span class="line"><span class="class"><span class="keyword">struct</span> <span class="title">msgbuf</span> </span></span><br><span class="line"><span class="class">&#123;</span></span><br><span class="line">	<span class="type">long</span> mtype;       <span class="comment">/* message type, must be &gt; 0 */</span></span><br><span class="line">	<span class="type">char</span> mtext[<span class="number">1</span>];    <span class="comment">/* message data */</span></span><br><span class="line">&#125;;</span><br></pre></td></tr></table></figure>
              </div>
            </details>

<ul>
<li><code>msgsz</code>：<code>size_t</code>类型，消息正文长度。</li>
<li><code>msgflg</code>：<code>int</code>类型，一些标志位，一般的话选择<code>0</code>。</li>
</ul>
<details class="folding-tag" blue><summary> 点击查看常用可取的值及含义 </summary>
              <div class='content'>
              <table>    <tr><td align="center" width=150px>0</td><td align="left">当消息队列满时，msgsnd将会阻塞，直到消息能写进消息队列</td></tr>    <tr><td align="center" width=150px>IPC_NOWAIT</td><td align="left">当消息队列已满的时候，msgsnd函数不等待立即返回</td></tr>    <tr><td align="center" width=150px>IPC_NOERROR</td><td align="left">若发送的消息大于size字节，则把该消息截断，截断部分将被丢弃，且不通知发送进程</td></tr></table><p>如果队列中的可用空间不足，那么<code>msgsnd()</code>的缺省行为是阻塞，直到空间可用为止。如果在<code>msgflg</code>中指定了<code>IPC_NOWAIT</code>，那么消息队列已满的时候调用将会失败并返回错误<code>EAGAIN</code>。</p>
              </div>
            </details>

<p><strong>【返回值】</strong><code>int</code>类型，成功返回<code>0</code>，失败返回<code>-1</code>，并设置<code>errno</code>。</p>
<p><strong>【使用格式】</strong>一般情况下基本使用格式如下：</p>
<figure class="highlight c"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment">/* 需要包含的头文件 */</span></span><br><span class="line"><span class="meta">#<span class="keyword">include</span> <span class="string">&lt;sys/types.h&gt;</span></span></span><br><span class="line"><span class="meta">#<span class="keyword">include</span> <span class="string">&lt;sys/ipc.h&gt;</span></span></span><br><span class="line"><span class="meta">#<span class="keyword">include</span> <span class="string">&lt;sys/msg.h&gt;</span></span></span><br><span class="line"><span class="comment">/* 至少应该有的语句 */</span></span><br><span class="line">msgT msg;<span class="comment">/* msgT 下边有介绍，是自定义的一种消息结构*/</span></span><br><span class="line">msgsnd(msgid, &amp;msgp, MSGLEN, <span class="number">0</span>);</span><br></pre></td></tr></table></figure>

<p><strong>【注意事项】</strong></p>
<p>（1）消息结构必须有<code>long</code>类型的<code>msg_type</code>字段，表示消息的类型。</p>
<p>（2）消息长度不包括首类型 <code>long</code>。</p>
<p>（3）<code>msgsnd()</code>解除阻塞的条件三个条件：第一，不满足消息队列满或个数满两个条件，即消息队列中有容纳该消息的空间；第二，<code>msqid</code>代表的消息队列被删除。第三，调用<code>msgsnd</code>函数的进程被信号中断。</p>
<h3 id="2-2-消息格式"><a href="#2-2-消息格式" class="headerlink" title="2.2 消息格式"></a><font size=3>2.2 消息格式</font></h3><p>我们发送消息之前，需要先了解一下消息的格式，有上边的消息发送函数以及消息在内核中的存储形式，我们知道，消息有类型和正文两个属性，于是我们就可以自定义一个结构体作为消息的格式，但是我们还需要知道消息正文内容的长度，这时候可以用宏定义。</p>
<figure class="highlight c"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment">/* 消息格式结构体 */</span></span><br><span class="line"><span class="keyword">typedef</span> <span class="class"><span class="keyword">struct</span></span></span><br><span class="line"><span class="class">&#123;</span></span><br><span class="line">	<span class="type">long</span> msg_type; <span class="comment">/* 消息类型 */</span></span><br><span class="line">	<span class="type">char</span> buf[<span class="number">128</span>]; <span class="comment">/* 消息内容 */</span></span><br><span class="line">&#125; msgT;</span><br><span class="line"><span class="meta">#<span class="keyword">define</span> MSGLEN  (sizeof(msgT)-sizeof(long))</span></span><br></pre></td></tr></table></figure>

<h3 id="2-3-使用实例"><a href="#2-3-使用实例" class="headerlink" title="2.3 使用实例"></a><font size=3>2.3 使用实例</font></h3><p>暂无。</p>
<h2 id="3-接收消息"><a href="#3-接收消息" class="headerlink" title="3. 接收消息"></a><font size=3>3. 接收消息</font></h2><h3 id="3-1-msgrcv"><a href="#3-1-msgrcv" class="headerlink" title="3.1 msgrcv() "></a><font size=3>3.1 msgrcv() </font></h3><p>在<code>linux</code>下可以使用<code>man 2 msgrcv</code>命令查看该函数的帮助手册。</p>
<figure class="highlight c"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment">/* 需包含的头文件 */</span></span><br><span class="line"><span class="meta">#<span class="keyword">include</span> <span class="string">&lt;sys/types.h&gt;</span></span></span><br><span class="line"><span class="meta">#<span class="keyword">include</span> <span class="string">&lt;sys/ipc.h&gt;</span></span></span><br><span class="line"><span class="meta">#<span class="keyword">include</span> <span class="string">&lt;sys/msg.h&gt;</span></span></span><br><span class="line"></span><br><span class="line"><span class="comment">/* 函数声明 */</span></span><br><span class="line"><span class="type">ssize_t</span> <span class="title function_">msgrcv</span><span class="params">(<span class="type">int</span> msqid, <span class="type">void</span> *msgp, <span class="type">size_t</span> msgsz, <span class="type">long</span> msgtyp, <span class="type">int</span> msgflg)</span>;</span><br></pre></td></tr></table></figure>

<p><strong>【函数说明】</strong>该函数从消息队列读取一个消息。</p>
<p><strong>【函数参数】</strong></p>
<ul>
<li><code>msqid</code>：<code>int</code>类型，消息队列<code>ID</code>。</li>
<li><code>msgp</code>：<code>void *</code>类型，要发送的消息的缓冲区地址，一般是指向一个我们<strong>自定义</strong>的<strong>特定格式</strong>的结构体变量，这个结构体变量中存储的是消息的类型和消息的正文。</li>
<li><code>msgsz</code>：<code>size_t</code>类型，指定要接收的消息正文长度。</li>
<li><code>msgtyp</code>：<code>long</code>类型，指定接收的消息类型。</li>
</ul>
<details class="folding-tag" blue><summary> 点击查看 msgtyp 取值范围的含义 </summary>
              <div class='content'>
              <table>    <tr><td align="center" width=150px>msgtype = 0</td><td align="left">收到的第一条消息，任意类型。</td></tr>    <tr><td align="center" width=150px>msgtype &gt; 0</td><td align="left">收到的第一条 msg_type类型的消息。</td></tr>    <tr><td align="center" width=150px>msgtype &lt; 0</td><td align="left">接收类型等于或者小于msgtype绝对值的第一个消息。</td></tr></table><p>例如，如果<code>msgtype=-4</code>，则只接受类型是<code>1</code>、<code>2</code>、<code>3</code>、<code>4</code>的消息 </p>
              </div>
            </details>

<ul>
<li><code>msgflg</code>：<code>int</code>类型，一些标志位，一般的话选择<code>0</code>。</li>
</ul>
<details class="folding-tag" blue><summary> 点击查看常用可取的值及含义 </summary>
              <div class='content'>
              <table>    <tr><td align="center" width=150px>0</td><td align="left">阻塞式接收消息，没有该类型的消息msgrcv函数一直阻塞等待</td></tr>    <tr><td align="center" width=150px>IPC_NOWAIT</td><td align="left">如果没有返回条件的消息调用立即返回，此时错误码为ENOMSG</td></tr>    <tr><td align="center" width=150px>MSG_EXCEPT</td><td align="left">与msgtype配合使用返回队列中第一个类型不为msgtype的消息</td></tr></table>
              </div>
            </details>

<p><strong>【返回值】</strong><code>ssize_t</code>类型，成功时返回收到的消息长度，失败返回<code>-1</code>，并设置<code>errno</code>。</p>
<p><strong>【使用格式】</strong>一般情况下基本使用格式如下：</p>
<figure class="highlight c"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment">/* 需要包含的头文件 */</span></span><br><span class="line"><span class="meta">#<span class="keyword">include</span> <span class="string">&lt;sys/types.h&gt;</span></span></span><br><span class="line"><span class="meta">#<span class="keyword">include</span> <span class="string">&lt;sys/ipc.h&gt;</span></span></span><br><span class="line"><span class="meta">#<span class="keyword">include</span> <span class="string">&lt;sys/msg.h&gt;</span></span></span><br><span class="line"><span class="comment">/* 至少应该有的语句 */</span></span><br><span class="line">msgT msg;<span class="comment">/* msgT 下边有介绍，是自定义的一种消息结构*/</span></span><br><span class="line">msgrcv(msgid, &amp;msg, MSGLEN, <span class="number">0</span>, <span class="number">0</span>);<span class="comment">/* 阻塞式接收任意类型消息 */</span></span><br></pre></td></tr></table></figure>

<p><strong>【注意事项】</strong></p>
<p>（1）消息结构必须有<code>long</code>类型的<code>msg_type</code>字段，表示消息的类型。</p>
<p>（2）消息长度不包括首类型 <code>long</code>。</p>
<h3 id="3-2-消息格式"><a href="#3-2-消息格式" class="headerlink" title="3.2 消息格式"></a><font size=3>3.2 消息格式</font></h3><p>我们读取的消息格式自然要与发送的消息格式相同啦。</p>
<figure class="highlight c"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment">/* 消息格式结构体 */</span></span><br><span class="line"><span class="keyword">typedef</span> <span class="class"><span class="keyword">struct</span></span></span><br><span class="line"><span class="class">&#123;</span></span><br><span class="line">	<span class="type">long</span> msg_type; <span class="comment">/* 消息类型 */</span></span><br><span class="line">	<span class="type">char</span> buf[<span class="number">128</span>]; <span class="comment">/* 消息内容 */</span></span><br><span class="line">&#125; msgT;</span><br><span class="line"><span class="meta">#<span class="keyword">define</span> MSGLEN  (sizeof(msgT)-sizeof(long))</span></span><br></pre></td></tr></table></figure>

<h3 id="3-3-使用实例"><a href="#3-3-使用实例" class="headerlink" title="3.3 使用实例"></a><font size=3>3.3 使用实例</font></h3><p>暂无。</p>
<h2 id="4-消息控制"><a href="#4-消息控制" class="headerlink" title="4.  消息控制"></a><font size=3>4.  消息控制</font></h2><h3 id="4-1-msgctl"><a href="#4-1-msgctl" class="headerlink" title="4.1 msgctl() "></a><font size=3>4.1 msgctl() </font></h3><p>在<code>linux</code>下可以使用<code>man 2 msgctl</code>命令查看该函数的帮助手册。</p>
<figure class="highlight c"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment">/* 需包含的头文件 */</span></span><br><span class="line"><span class="meta">#<span class="keyword">include</span> <span class="string">&lt;sys/types.h&gt;</span></span></span><br><span class="line"><span class="meta">#<span class="keyword">include</span> <span class="string">&lt;sys/ipc.h&gt;</span></span></span><br><span class="line"><span class="meta">#<span class="keyword">include</span> <span class="string">&lt;sys/msg.h&gt;</span></span></span><br><span class="line"><span class="comment">/* 函数声明 */</span></span><br><span class="line"><span class="type">int</span> <span class="title function_">msgctl</span><span class="params">(<span class="type">int</span> msqid, <span class="type">int</span> cmd, <span class="keyword">struct</span> msqid_ds *buf)</span>;</span><br></pre></td></tr></table></figure>

<p><strong>【函数说明】</strong>该函数用于控制消息队列，例如，修改一个消息队列控制权限，删除一个消息队列。</p>
<p><strong>【函数参数】</strong></p>
<ul>
<li><code>msqid</code>：<code>int</code>类型，消息队列<code>ID</code>。</li>
<li><code>cmd</code>：<code>int</code>类型，表示要执行的操作。</li>
</ul>
<details class="folding-tag" blue><summary> 点击查看 cmd 常用值几含义 </summary>
              <div class='content'>
              <table>    <tr><td align="center" width=150px>IPC_STAT</td><td align="left">把msqid_ds结构中的数据设置为消息队列的当前关联值，和*buf参数配合获取msqid消息队列信息</td></tr>    <tr><td align="center" width=150px>IPC_SET </td><td align="left">在进程有足够权限的前提下，把消息队列的当前关联值设置为msqid_ds数据结构中给的值</td></tr>    <tr><td align="center" width=150px>IPC_RMID</td><td align="left">删除消息队列</td></tr></table>
              </div>
            </details>

<ul>
<li><code>buf</code>：<code>struct msqid_ds</code>类型结构体指针变量，指向存储消息队列相关信息的结构体，一般是设置为<code>NULL</code>。</li>
</ul>
<details class="folding-tag" blue><summary> 点击查看 struct msqid_ds 成员 </summary>
              <div class='content'>
              <figure class="highlight c"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br></pre></td><td class="code"><pre><span class="line"><span class="class"><span class="keyword">struct</span> <span class="title">msqid_ds</span></span></span><br><span class="line"><span class="class">&#123;</span></span><br><span class="line">	<span class="class"><span class="keyword">struct</span> <span class="title">ipc_perm</span> <span class="title">msg_perm</span>;</span>   <span class="comment">/* Ownership and permissions */</span></span><br><span class="line">	<span class="type">time_t</span>          msg_stime;  <span class="comment">/* Time of last msgsnd(2) */</span></span><br><span class="line">	<span class="type">time_t</span>          msg_rtime;  <span class="comment">/* Time of last msgrcv(2) */</span></span><br><span class="line">	<span class="type">time_t</span>          msg_ctime;  <span class="comment">/* Time of creation or last</span></span><br><span class="line"><span class="comment">                                              modification by msgctl() */</span></span><br><span class="line">	<span class="type">unsigned</span> <span class="type">long</span>   msg_cbytes; <span class="comment">/* # of bytes in queue */</span></span><br><span class="line">	<span class="type">msgqnum_t</span>       msg_qnum;   <span class="comment">/* # number of messages in queue */</span></span><br><span class="line">	<span class="type">msglen_t</span>        msg_qbytes; <span class="comment">/* Maximum # of bytes in queue */</span></span><br><span class="line">	<span class="type">pid_t</span>           msg_lspid;  <span class="comment">/* PID of last msgsnd(2) */</span></span><br><span class="line">	<span class="type">pid_t</span>           msg_lrpid;  <span class="comment">/* PID of last msgrcv(2) */</span></span><br><span class="line">&#125;;</span><br></pre></td></tr></table></figure>
              </div>
            </details>

<p><strong>【返回值】</strong><code>int</code>类型，成功时，<code>cmd</code>取<code>IPC_STAT</code>, <code> IPC_SET</code>或者 <code>IPC_RMID</code> 返回<code>0</code>，失败返回<code>-1</code>，并设置<code>errno</code>。</p>
<p><strong>【使用格式】</strong>一般情况下基本使用格式如下：</p>
<figure class="highlight c"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment">/* 需要包含的头文件 */</span></span><br><span class="line"><span class="meta">#<span class="keyword">include</span> <span class="string">&lt;sys/types.h&gt;</span></span></span><br><span class="line"><span class="meta">#<span class="keyword">include</span> <span class="string">&lt;sys/ipc.h&gt;</span></span></span><br><span class="line"><span class="meta">#<span class="keyword">include</span> <span class="string">&lt;sys/msg.h&gt;</span></span></span><br><span class="line"><span class="comment">/* 至少应该有的语句 */</span></span><br><span class="line">msgT msg;<span class="comment">/* msgT 下边有介绍，是自定义的一种消息结构*/</span></span><br><span class="line">msgrcv(msgid, &amp;msg, MSGLEN, <span class="number">0</span>, <span class="number">0</span>);<span class="comment">/* 阻塞式接收任意类型消息 */</span></span><br></pre></td></tr></table></figure>

<p><strong>【注意事项】</strong>该函数的返回值还有其他的情况，只是我们一般是使用上边写出的三个参数，需要使用其他参数的话，可以查看帮助手册。</p>
<h3 id="4-2-使用实例"><a href="#4-2-使用实例" class="headerlink" title="4.2 使用实例"></a><font size=3>4.2 使用实例</font></h3><p>暂无。</p>
<h1 id="三、消息队列实例"><a href="#三、消息队列实例" class="headerlink" title="三、消息队列实例"></a><font size=3>三、消息队列实例</font></h1><h2 id="1-msg-send-c"><a href="#1-msg-send-c" class="headerlink" title="1. msg_send.c"></a><font size=3>1. msg_send.c</font></h2><details class="folding-tag" blue><summary> 点击查看详情 </summary>
              <div class='content'>
              <figure class="highlight c"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br><span class="line">40</span><br><span class="line">41</span><br><span class="line">42</span><br><span class="line">43</span><br><span class="line">44</span><br><span class="line">45</span><br><span class="line">46</span><br><span class="line">47</span><br><span class="line">48</span><br><span class="line">49</span><br><span class="line">50</span><br><span class="line">51</span><br><span class="line">52</span><br><span class="line">53</span><br><span class="line">54</span><br><span class="line">55</span><br><span class="line">56</span><br><span class="line">57</span><br><span class="line">58</span><br><span class="line">59</span><br><span class="line">60</span><br><span class="line">61</span><br><span class="line">62</span><br><span class="line">63</span><br><span class="line">64</span><br><span class="line">65</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment">/* 头文件 */</span></span><br><span class="line"><span class="meta">#<span class="keyword">include</span> <span class="string">&lt;stdio.h&gt;</span>  <span class="comment">/* perror sprintf*/</span></span></span><br><span class="line"><span class="meta">#<span class="keyword">include</span> <span class="string">&lt;sys/ipc.h&gt;</span><span class="comment">/* msgget msgsnd ftok */</span></span></span><br><span class="line"><span class="meta">#<span class="keyword">include</span> <span class="string">&lt;sys/msg.h&gt;</span><span class="comment">/* msgget msgsnd */</span></span></span><br><span class="line"><span class="meta">#<span class="keyword">include</span> <span class="string">&lt;string.h&gt;</span> <span class="comment">/* strcpy */</span></span></span><br><span class="line"><span class="meta">#<span class="keyword">include</span> <span class="string">&lt;stdlib.h&gt;</span> <span class="comment">/* system */</span></span></span><br><span class="line"></span><br><span class="line"><span class="comment">/* 消息格式结构体 */</span></span><br><span class="line"><span class="keyword">typedef</span> <span class="class"><span class="keyword">struct</span></span></span><br><span class="line"><span class="class">&#123;</span></span><br><span class="line">	<span class="type">long</span> msg_type; <span class="comment">/* 消息类型 */</span></span><br><span class="line">	<span class="type">char</span> buf[<span class="number">128</span>]; <span class="comment">/* 消息内容 */</span></span><br><span class="line">&#125; msgT;</span><br><span class="line"><span class="meta">#<span class="keyword">define</span> MSGLEN  (sizeof(msgT)-sizeof(long))</span></span><br><span class="line"></span><br><span class="line"><span class="comment">/* 主函数 */</span></span><br><span class="line"><span class="type">int</span> <span class="title function_">main</span><span class="params">(<span class="type">int</span> argc, <span class="type">char</span> *argv[])</span></span><br><span class="line">&#123;</span><br><span class="line">	<span class="type">int</span> ret;</span><br><span class="line">	<span class="type">key_t</span> key;</span><br><span class="line">	<span class="type">int</span> msgid;</span><br><span class="line">	msgT msg;</span><br><span class="line"></span><br><span class="line">	<span class="type">int</span> i = <span class="number">0</span>;</span><br><span class="line">	<span class="type">char</span> buff[<span class="number">50</span>];</span><br><span class="line"></span><br><span class="line">	<span class="comment">/* 1. 生成key */</span></span><br><span class="line">	key = ftok(<span class="string">&quot;./key.txt&quot;</span>, <span class="number">100</span>);</span><br><span class="line">	<span class="keyword">if</span>(key &lt; <span class="number">0</span>)</span><br><span class="line">	&#123;</span><br><span class="line">		perror(<span class="string">&quot;ftok&quot;</span>);</span><br><span class="line">		<span class="keyword">return</span> <span class="number">-1</span>;</span><br><span class="line">	&#125;</span><br><span class="line">	<span class="comment">/* 2. 打开或创建消息队列 */</span></span><br><span class="line">	msgid = msgget(key, IPC_CREAT|<span class="number">0666</span>);</span><br><span class="line">	<span class="keyword">if</span>(msgid &lt; <span class="number">0</span>)</span><br><span class="line">	&#123;</span><br><span class="line">		perror(<span class="string">&quot;msgget&quot;</span>);</span><br><span class="line">		<span class="keyword">return</span> <span class="number">-1</span>;</span><br><span class="line">	&#125;</span><br><span class="line">	<span class="comment">/* 3. 发送消息 */</span></span><br><span class="line">	<span class="keyword">for</span>(i = <span class="number">0</span>; i &lt; <span class="number">6</span>; i++)<span class="comment">/* 发送5 */</span></span><br><span class="line">	&#123;</span><br><span class="line">		<span class="keyword">if</span>(i &gt; <span class="number">3</span>)</span><br><span class="line">		&#123;</span><br><span class="line">			msg.msg_type = <span class="number">3</span>;<span class="comment">/* 消息类型 */</span></span><br><span class="line">		&#125;</span><br><span class="line">		<span class="keyword">else</span></span><br><span class="line">		&#123;</span><br><span class="line">			msg.msg_type = <span class="number">1</span>;<span class="comment">/* 消息类型 */</span></span><br><span class="line">		&#125;</span><br><span class="line">		<span class="built_in">sprintf</span>(buff, <span class="string">&quot;This message type is %d!&quot;</span>, (<span class="type">int</span>)msg.msg_type);</span><br><span class="line">		</span><br><span class="line">		<span class="built_in">strcpy</span>(msg.buf, buff);<span class="comment">/* 消息内容 */</span></span><br><span class="line">		ret = msgsnd(msgid, &amp;msg, MSGLEN, <span class="number">0</span>);</span><br><span class="line">		<span class="keyword">if</span>(ret &lt; <span class="number">0</span>)</span><br><span class="line">		&#123;</span><br><span class="line">			perror(<span class="string">&quot;msgsnd&quot;</span>);</span><br><span class="line">			<span class="keyword">return</span> <span class="number">-1</span>;</span><br><span class="line">		&#125;</span><br><span class="line">		<span class="built_in">printf</span>(<span class="string">&quot;Send message [%s] success!\n&quot;</span>, msg.buf);</span><br><span class="line">	&#125;</span><br><span class="line">	system(<span class="string">&quot;ipcs -q&quot;</span>);</span><br><span class="line">	<span class="keyword">return</span> <span class="number">0</span>;</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>
              </div>
            </details>

<h2 id="2-msg-receive-c"><a href="#2-msg-receive-c" class="headerlink" title="2. msg_receive.c"></a><font size=3>2. msg_receive.c</font></h2><details class="folding-tag" blue><summary> 点击查看详情 </summary>
              <div class='content'>
              <figure class="highlight c"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br><span class="line">40</span><br><span class="line">41</span><br><span class="line">42</span><br><span class="line">43</span><br><span class="line">44</span><br><span class="line">45</span><br><span class="line">46</span><br><span class="line">47</span><br><span class="line">48</span><br><span class="line">49</span><br><span class="line">50</span><br><span class="line">51</span><br><span class="line">52</span><br><span class="line">53</span><br><span class="line">54</span><br><span class="line">55</span><br><span class="line">56</span><br><span class="line">57</span><br><span class="line">58</span><br><span class="line">59</span><br><span class="line">60</span><br><span class="line">61</span><br><span class="line">62</span><br><span class="line">63</span><br><span class="line">64</span><br><span class="line">65</span><br><span class="line">66</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment">/* 头文件 */</span></span><br><span class="line"><span class="meta">#<span class="keyword">include</span> <span class="string">&lt;stdio.h&gt;</span>  <span class="comment">/* perror */</span></span></span><br><span class="line"><span class="meta">#<span class="keyword">include</span> <span class="string">&lt;sys/ipc.h&gt;</span><span class="comment">/* msgget msgsnd ftok */</span></span></span><br><span class="line"><span class="meta">#<span class="keyword">include</span> <span class="string">&lt;sys/msg.h&gt;</span><span class="comment">/* msgget msgsnd */</span></span></span><br><span class="line"><span class="meta">#<span class="keyword">include</span> <span class="string">&lt;string.h&gt;</span> <span class="comment">/* strcpy */</span></span></span><br><span class="line"><span class="meta">#<span class="keyword">include</span> <span class="string">&lt;stdlib.h&gt;</span> <span class="comment">/* system */</span></span></span><br><span class="line"></span><br><span class="line"><span class="comment">/* 消息格式结构体 */</span></span><br><span class="line"><span class="keyword">typedef</span> <span class="class"><span class="keyword">struct</span></span></span><br><span class="line"><span class="class">&#123;</span></span><br><span class="line">	<span class="type">long</span> msg_type; <span class="comment">/* 消息类型 */</span></span><br><span class="line">	<span class="type">char</span> buf[<span class="number">128</span>]; <span class="comment">/* 消息内容 */</span></span><br><span class="line">&#125; msgT;</span><br><span class="line"><span class="meta">#<span class="keyword">define</span> MSGLEN  (sizeof(msgT)-sizeof(long))</span></span><br><span class="line"></span><br><span class="line"><span class="comment">/* 主函数 */</span></span><br><span class="line"><span class="type">int</span> <span class="title function_">main</span><span class="params">(<span class="type">int</span> argc, <span class="type">char</span> *argv[])</span></span><br><span class="line">&#123;</span><br><span class="line">	<span class="type">int</span> ret;</span><br><span class="line">	<span class="type">int</span> count = <span class="number">0</span>;</span><br><span class="line">	<span class="type">key_t</span> key;</span><br><span class="line">	<span class="type">int</span> msgid;</span><br><span class="line">	msgT msg;</span><br><span class="line"></span><br><span class="line">	<span class="comment">/* 1. 生成key */</span></span><br><span class="line">	key = ftok(<span class="string">&quot;./key.txt&quot;</span>, <span class="number">100</span>);</span><br><span class="line">	<span class="keyword">if</span>(key &lt; <span class="number">0</span>)</span><br><span class="line">	&#123;</span><br><span class="line">		perror(<span class="string">&quot;ftok&quot;</span>);</span><br><span class="line">		<span class="keyword">return</span> <span class="number">-1</span>;</span><br><span class="line">	&#125;</span><br><span class="line">	<span class="comment">/* 2. 打开或创建消息队列 */</span></span><br><span class="line">	msgid = msgget(key, IPC_CREAT|<span class="number">0666</span>);</span><br><span class="line">	<span class="keyword">if</span>(msgid &lt; <span class="number">0</span>)</span><br><span class="line">	&#123;</span><br><span class="line">		perror(<span class="string">&quot;msgget&quot;</span>);</span><br><span class="line">		<span class="keyword">return</span> <span class="number">-1</span>;</span><br><span class="line">	&#125;</span><br><span class="line">	<span class="comment">/* 3. 接收消息 */</span></span><br><span class="line">	<span class="keyword">while</span>(<span class="number">1</span>)</span><br><span class="line">	&#123;</span><br><span class="line">		ret = msgrcv(msgid, &amp;msg, MSGLEN, <span class="number">0</span>, <span class="number">0</span>);<span class="comment">/* 阻塞式接收任意类型消息 */</span></span><br><span class="line">		<span class="keyword">if</span>(ret &lt; <span class="number">0</span>)</span><br><span class="line">		&#123;</span><br><span class="line">			perror(<span class="string">&quot;msgrcv&quot;</span>);</span><br><span class="line">			<span class="keyword">return</span> <span class="number">-1</span>;</span><br><span class="line">		&#125;</span><br><span class="line">		<span class="built_in">printf</span>(<span class="string">&quot;[count=%d]receive message type=%d,buf=%s\n&quot;</span>, count, (<span class="type">int</span>)msg.msg_type, msg.buf);</span><br><span class="line">		count++;</span><br><span class="line">		<span class="keyword">if</span>(count &gt; <span class="number">5</span>)</span><br><span class="line">		&#123;</span><br><span class="line">			<span class="keyword">break</span>;</span><br><span class="line">		&#125;</span><br><span class="line">	&#125;</span><br><span class="line">	system(<span class="string">&quot;ipcs -q&quot;</span>);</span><br><span class="line">	<span class="comment">/* 4. 删除消息队列 */</span></span><br><span class="line">	<span class="built_in">printf</span>(<span class="string">&quot;\n==============Delete=================\n&quot;</span>);</span><br><span class="line">	ret = msgctl(msgid, IPC_RMID, <span class="literal">NULL</span>);</span><br><span class="line">	<span class="keyword">if</span>(ret &lt; <span class="number">0</span>)</span><br><span class="line">	&#123;</span><br><span class="line">		perror(<span class="string">&quot;msgctl&quot;</span>);</span><br><span class="line">		<span class="keyword">return</span> <span class="number">-1</span>;</span><br><span class="line">	&#125;</span><br><span class="line">	system(<span class="string">&quot;ipcs -q&quot;</span>);</span><br><span class="line">	<span class="keyword">return</span> <span class="number">0</span>;</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>
              </div>
            </details>

<h2 id="3-makefile"><a href="#3-makefile" class="headerlink" title="3. makefile"></a><font size=3>3. makefile</font></h2><details class="folding-tag" blue><summary> 点击查看详情 </summary>
              <div class='content'>
              <figure class="highlight makefile"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br></pre></td><td class="code"><pre><span class="line">CC = gcc</span><br><span class="line"></span><br><span class="line">DEBUG = -g -O2 -Wall</span><br><span class="line">CFLAGS += <span class="variable">$(DEBUG)</span></span><br><span class="line"></span><br><span class="line"><span class="comment"># 所有.c文件去掉后缀</span></span><br><span class="line">TARGET_LIST = $&#123;patsubst %.c, %, $&#123;wildcard *.c&#125;&#125; </span><br><span class="line"></span><br><span class="line">all : <span class="variable">$(TARGET_LIST)</span></span><br><span class="line"></span><br><span class="line">%.o : %.c</span><br><span class="line">	<span class="variable">$(CC)</span> <span class="variable">$(CFLAGS)</span> -c <span class="variable">$&lt;</span> -o <span class="variable">$@</span></span><br><span class="line"></span><br><span class="line"><span class="meta"><span class="keyword">.PHONY</span>: all clean clean_o</span></span><br><span class="line">clean : clean_o</span><br><span class="line">	@rm -vf <span class="variable">$(TARGET_LIST)</span> </span><br><span class="line">	</span><br><span class="line">clean_o :</span><br><span class="line">	@rm -vf *.o</span><br></pre></td></tr></table></figure>
              </div>
            </details>

<h2 id="4-编译与测试"><a href="#4-编译与测试" class="headerlink" title="4. 编译与测试"></a><font size=3>4. 编译与测试</font></h2><p>在终端执行以下命令编译程序：</p>
<figure class="highlight shell"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line">make # 生成可执行文件</span><br><span class="line">./msg_send        # 向消息队列发送消息</span><br><span class="line">./msg_receive     # 从消息队列读取消息</span><br></pre></td></tr></table></figure>

<p>然后，终端会有以下信息显示：</p>
<figure class="highlight shell"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br></pre></td><td class="code"><pre><span class="line"><span class="meta prompt_"># </span><span class="language-bash">执行 ./msg_send</span></span><br><span class="line">Send message [This message type is 1!] success!</span><br><span class="line">Send message [This message type is 1!] success!</span><br><span class="line">Send message [This message type is 1!] success!</span><br><span class="line">Send message [This message type is 1!] success!</span><br><span class="line">Send message [This message type is 3!] success!</span><br><span class="line">Send message [This message type is 3!] success!</span><br><span class="line"></span><br><span class="line">--------- 消息队列 -----------</span><br><span class="line">键        msqid      拥有者  权限     已用字节数 消息      </span><br><span class="line">0x643d0b4e 5          hk         666        768          6</span><br><span class="line"><span class="meta prompt_"></span></span><br><span class="line"><span class="meta prompt_"># </span><span class="language-bash">执行 ./msg_receive</span></span><br><span class="line">[count=0]receive message type=1,buf=This message type is 1!</span><br><span class="line">[count=1]receive message type=1,buf=This message type is 1!</span><br><span class="line">[count=2]receive message type=1,buf=This message type is 1!</span><br><span class="line">[count=3]receive message type=1,buf=This message type is 1!</span><br><span class="line">[count=4]receive message type=3,buf=This message type is 3!</span><br><span class="line">[count=5]receive message type=3,buf=This message type is 3!</span><br><span class="line"></span><br><span class="line">--------- 消息队列 -----------</span><br><span class="line">键        msqid      拥有者  权限     已用字节数 消息      </span><br><span class="line">0x643d0b4e 5          hk         666        0            0           </span><br><span class="line"></span><br><span class="line"></span><br><span class="line">==============Delete=================</span><br><span class="line"></span><br><span class="line">--------- 消息队列 -----------</span><br><span class="line">键        msqid      拥有者  权限     已用字节数 消息</span><br></pre></td></tr></table></figure>


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